Abstract: During staged bridge plug fracturing in horizontal wells, the stimulation effects of each cluster can not be monitored in real time manner. To address this challenge, an external fiber optic monitoring completion string for staged bridge plug fracturing in horizontal wells was designed. The specialized wear-resistant armored optical cable and the cable traversing corrector enable the safe entry of the optical cable into the well. The wellhead optical cable gate valve penetration, external cable azimuth magnetic flux detection (positioning error ≤ 3°) and the bilinear directional perforation avoidance method effectively ensure the integrity of the cable during the operation , enabling continuous transmission of fiber optic signals underground. Field trials were conducted in Xinjiang Oilfield, validating the technology's ability to achieve real-time online monitoring of dynamic information during fracturing, such as clustering perforation, fluid intake into each cluster, bridge plug sealing as well as temporary plugging and diversion. This technology provides a new idea and method for real-time monitoring the staged fracturing effects of unconventional oil and gas horizontal wells.